It is known that wholly aromatic esters are suitable for use in molding compositions. The synthesis of wholly aromatic polyesters of the type with which the present invention is principally concerned is disclosed in U.S. Pat. No. 3,637,595, entitled, "p-Oxybenzoyl Copolyester", the disclosure of which is incorporated herein by reference. Other patents disclosing the molding properties of aromatic polyesters, more particularly of oxybenzoyl polyesters are U.S. Pat. Nos. 3,662,052, 3,849,362 and 4,219,629.
Another group of aromatic polyesters which can be employed are the aromatic polyesters containing recurring units of the 2,6-dicarboxynaphthalene moiety and/or the p-oxybenzoyl moiety and symmetrical dioxy aryl moiety, and variations thereof. Such polyesters are disclosed in U.S. Pat. Nos. 4,067,852; 4,083,829; 4,130,545; 4,161,470; 4,184,996; 4,219,461; 4,224,433, 4,238,598; 4,238,599; 4,256,624; 4,265,802; 4,279,803, 4,318,841 and 4,318,842.
The oxybenzoyl polyesters useful in the present invention can be employed with various fillers of types and in amounts which either promote or at a minimum do not materially affect the desired properties. Examples of suitable fillers include among others glass fibers, milled glass, polytetrafluoroethylene, pigments and talc and known conventional fillers and combinations thereof.
In a particular application of molding compositions based on oxybenzoyl polyesters, novel ovenware which can be used in both thermal and microwave ovens has been provided as described in copending and commonly assigned application Ser. No. 450,949, now abandoned, entitled "Plastic Ovenware", the disclosure of which is incorporated herein by reference.
A further improvement in the production of such ovenware wherein talc of a particular quality is employed as a filler is disclosed in copending and commonly assigned application Ser. No. 401765, entitled "Improved Plastic Ovenware Containing Talc", the disclosure of which is likewise incorporated herein by reference.
Continuing effort continues to be expended on the development of more effective molding compositions and improvements in the molding procedure.